The present invention relates generally to a device for wide band fiber optics communication. More particularly, the present invention relates to using electrostatic modulators in communication applications.
Fiber optic transmitters have a wide variety of applications, especially in the communications industry. Commonly, a fiber optic transmitter includes an amplifier for sending a signal over a long distance. Such a transmitter frequently includes a laser source of a given wavelength, an optical isolator, a modulator to modulate the laser output, and an amplifier.
Modulation of the laser output may be accomplished using a variety of techniques. Transmitters sometimes utilize a direct drive approach to modulate the light source, such as rapidly varying the intensity of the light source. In order to increase the amount of information that may be transmitted, arrays of direct drive diodes have been directly modulated to produce a wideband signal.
Other methods include modulating an existing carrier signal to impress a data stream on the carrier signal. These methods typically use traditional electrooptic, fiber, or digital modulators. Such methods may separate the frequencies of a wideband signal to modulate individual frequencies with different information followed by recombining the modulated frequencies.
Another method for modulating an optical signal is to use a grating light valve (GLV), which offers the ability to perform multi-element modulation. The GLV is an addressable diffraction grating, formed of moving parts on the surface of a silicon chip. Each GLV assembly can have between about 1,000 and 8,000 picture elements where each picture pixel element has six ribbons of silicon. The GLV relies upon the linear nature of the electric and magnetic fields of light or image construction using constructive and destructive interference. This application is typically found within the video arts where the GLV serves as a projector.
A GLV modulator operates on the principles of an attractive electrostatic force being produced by a voltage difference between a conductive substrate and a conducting layer atop a ribbon layer. The attractive force changes the heights of the ribbons relative to the substrate. By modulating the voltage waveform, it is possible to modulate the diffracted optical beam as needed.
Fiber optic modulators are electronically controlled devices that modulate light intensity and are designed to be compatible with optical fibers. However, there is a need for low power, high efficiency, and low loss, inexpensive fiber optic modulators that can be integrated with silicon sensors and electronics and be further optimized for communications with fast transmission speeds.